Last week's Switched On discussed the Slacker Portable, Sony eMarker and TrafficGauge, three dedicated devices that didn't make it but saw their functionality ultimately realized via smartphones. But there have been other idea for which the idea ultimately proved popular as smartphone bits rather than separately packaged atoms.

Kodak EasyShare Picture Viewer

Compared to some of the devices in this and the previous column, the idea of a portable digital picture viewer -- essentially a pocket-sized, battery-powered digital picture frame with a smartphone-sized display -- has been relatively successful. In addition to the Kodak product, which required the company's software for optimal photo transfers, companies such as HP and Brookstone have dabbled in this market, and a recent glance behind the cashier counter at a local drug store revealed one by Smartparts, which sells the devices via Amazon.

It's easy to see how these simple digital "brag books" might be favored by grandparents that don't otherwise see the need for a Droid, Lumia or Galaxy device, but clearly this niche category has been dwarfed by smartphones, many of which can show at least one photo of your precious without even unlocking the screen.

Modo.net

In the days when the Vindigo city guide was a killer app for Palm PDAs, a startup with the strange name of Scout Electromedia sought to upstage it with an inexpensive hipster-targeted pocket device that provided up-to-the-minute updates on goings-on about town. The oddly shaped Modo came in a few color combinations and included a small monochrome LCD protected by a silicone cover that could be tucked behind the device when in use. Like the TrafficGauge discussed in last week's Switched On, data for the Modo arrived via the paging network. Unlike the TrafficGauge, the lifetime service was free (as was the monthly fee for the lifetime service).

Alas, it wasn't much of a lifetime. Modo spent big on billboards in launch cities of New York and San Francisco, but you might have missed its window of availability if you blinked. The service shut down within a few months of launch, creating a smattering of colorful LCD-equipped paperweights. These days, any number of mobile apps and Web sites can provide updated info on events and hotspots. The Local Scout app on Windows Phones is among those that best carry on its spirit.

Smart Display

While the connectivity, ubiquity and carrier subsidization of smartphones make them a triple threat, tablets have also had an impact on several device types that attained a degree of traction, such as netbooks and e-readers. But, as with the smartphone, there's at least one failed product that has seen a kind of second life on tablets.

Hailing it as as the future of the (small) monitor whereas Tablet PCs were the future of the notebook, Microsoft introduced Smart Display in 2002 and killed it less than a year after the first models shipped. The Smart Display was a tablet-like device complete with a (resistive) touchscreen) designed to enable wireless control of a Windows PC within the home. It did this functionally if not impressively quickly using Microsoft's Remote Display Protocol over the slower Wi-Fi networks available at the time. Portending a dilemma faced even on today's tablets, ViewSonic, an early supporter, offered a (wired) keyboard for its two models. Like any new technology, Smart Displays had their share of quirks, but what really made them dead on arrival were their $1,000+ price.

These days, a number of free tablet apps can essentially turn any iPad or Android tablet into a functional Smart Display for Windows PCs or Macs.

These days, a number of free tablet apps can essentially turn any iPad or Android tablet into a functional Smart Display for Windows PCs or Macs. However, these tablets, particularly when combined with cloud storage services such as Dropbox or a product such as PogoPlug, can themselves more conveniently handle many of the tasks that justified remotely connecting to a PC. The posthumous victory of the Smart Display concept, then, is only a partial one. Were the desktop monitor market not being assailed by all-in-ones, notebooks and tablets, it might be interesting to see something like an Android-powered monitor that could be used without necessarily turning on the PC.

Had more of these devices survived long enough to see today's adoption of smartphones and tablets, the older products surely would have been vanquished by today's diversified devices that are faring so well against products that have been far more popular. Today, any company thinking of producing a new kind of digital device must seriously consider the risk that such a product's functionality can be matched by smartphone-resident apps and a potential accessory (a lesson more recently learned by mobile e-mail appliance maker Peek, which has refocused its business on software and cloud services for other handsets).

It's a tall enough hurdle that we may not see many try. Indeed, these smartphone-competitive portable gadgets may have hit the pavement, but they may have been among the last to make it through the launch window before it closed forever.

Ross Rubin (@rossrubin) is executive director and principal analyst of the NPD Connected Intelligence service at The NPD Group. Views expressed in Switched On are his own.